Here is the full list of all 26 SUPERHOT achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Kill over 1987 Red Dudes in endless mode.
Beat all Challenges.
Get RED ending in every level of SPEEDRUN challenge.
Get RED ending in every level of SPEEDRUNrt challenge.
Launch every app in the system.
Kill 100 Red Dudes with a rifle.
Unlock all endless levels.
Upload a replay on killstagram.com
Become part of the community.
Find all secrets.
Kill 100 Red Dudes with a katana.
Complete the game.
Score 100 headshots.
Kill 100 Red Dudes with a shotgun.
Get back to the system after being expelled.
Kill 3 Red Dudes with one shotgun shot.
Kill 100 Red Dudes with a pistol.
Cut bullet with a katana.
Kill 2 Red Dudes with one katana throw.
Complete SERV level.
Kill 3 Red Dudes with one rifle burst.
Kill 100 Red Dudes using melee.
Complete SUBWAY level.
Shoot down a bullet with a bullet.
Kill an enemy by jumping on him.